The Soil Moisture Active Passive mission (SMAP) was launched in 2015 as the first NASA satellite dedicated to measuring the water content of soils. The satellite uses a radiometer to measure soil moisture in the top 5 centimeters of the ground.

The advance-and-retreat cycle of snow cover drastically changes the whiteness and brightness of Earth. Using these two 2017 maps created using NASA satellite data, have students review the seasonal differences of snow and ice extent.